''no signal'' message on blue screen after watching for 10-30 min

Might have been a power spike that flashed channel memory. try rescanning for channels. And make sure physically that you antennas wiring is good and anywhere on it. post what you find good luck...

with the blue screen do you see any kind of error message or any blink code?

if so we can solve the error very easily

Blue is no signal, first see if rear inputs work with a DVD etc connected as this will rule some things out.

If using for example a cable or satellite box, remove it and the set from power for several minutes and then power both back up which would allow them to try to reboot.

One of the things an HDMI connection does is allow the TV and equipment to talk back and forth to each other. When you turn the TV off it ends this connection but when you turn it back on, it doesn't communicate correctly. The analog inputs don't do this that's why when you change inputs and go back to HDMI it works, because the TV reestablishes that connection. You didn't list the model of the TV but go to "http://www.csd.toshiba.com/cgi-bin/tais/support/jsp/home.jsp" and click download. Enter the TV you have and click "GO". A list of downloads comes up and your TV may have a firmware update for it. There is instructions on how to do it. Even if this doesn't fix this problem, it is still good to do to avoid other problems. Another solution is to use component (Red/Blue/Green) cables. The highest resolution they support is 1080i, HDMI is 1080p. Depending on the model of your TV and what your watching though, you might not see a difference. TV2 will never have this problem because it is not connected through HDMI.

It sounds like you have no signal being detected by the TV. Check your connections to the TV from your cable box or satelite reciever to be sure they're plugged in tightly. If you have a DVD player or VCR, try watching something from one of them to see if you get a picture. If you do, then your problem may be with your cable box or satelite reciever, and not the TV.
Good luck.

Check the cable connector. If it is OK then the turner has gone bad. Replace main board will fix it.

You need to replace the surface mounted voltage regulator IC (small black square chip with a metal tab on one end, and two legs on the other end.) it is on the main board, right behind the signal input board. It's a BA09FP regulator IC, you can purchase this on mouser.com

it requires a bit of disassembly, but it is relatively easy to do. it is component number IC9C25. It could be bad, or just have bad connections . This IC supplies 9 volts to the terminal board. Try resolding it first.

I have the same problem. It seems the tv is switching from composite1 to composite 2 source.

My HDMI has stopped working. I have had a technician from Dish network out to my house 3 times and they have replaced the receiver and the HDMI cable and were unable to get the set to work all I get is a blue screen and a message which reads no signal. I also cannot use mt set using 3 rca cables connected to the component input when set to 1080 I keep intermittenly get a black screen then a blue screeen and sometimes a no signal message. I have to watch the tv set to 720 on component 2 and it is the most stable in that setting. Please send help

I just spent an hour trying to fix the VIZIO with the same problem. The screen had no picture at all, but could hear the sound perfectly!! But we i figured out the solution! UNPLUG THE CABLE BOX AND LET IT RE-BOOT! and it WORKED!!!!!